I didn't find her in Ancestry or Familysearch.org but I didn't really expect to find her. Alaska publishes or allows to be published just about nothing.
However, it's been 50 years since a divorce record or death record would have been issued. Therefore, those records are now are considered public and you can request them from Alaskta Vital Records, http://genealogy.about.com/od/vital_records/p/alaska.htm
Before you contact them, do you have a copy of Ralph's obituary? I don't know if one would have been published since he didn't have children.
I don't have a contact for obituaries there, but do a Google search for the Yukon or Nenana Public Library and ask if they have an obituary file.
If the Informant was knowledgeable, there might be more information on Ralph's death certificate. The Spouse field should be filled in or shown as divorced or widower. Successful Searching!